Radiative and Dynamical Influences on Polar Stratospheric Temperature Trends

Radiative and dynamical heating rates control stratospheric temperatures. In this study, radiative temperature trends due to ozone depletion and increasing well-mixed greenhouse gases from 1980 to 2000 in the polar stratosphere are directly evaluated, and the dynamical contributions to temperature trends are estimated as the residual between the observed and radiative trends. The radiative trends are obtained from a seasonally evolving fixed dynamical heating calculation with the Parallel Offline Radiative Transfer model using four different ozone datasets, which provide estimates of observed ozone changes. In the spring and summer seasons, ozone depletion leads to radiative cooling in the lower stratosphere in the Arctic and Antarctic. In Arctic summer there is weak wave driving, and the radiative cooling due to ozone depletion is the dominant driver of observed trends. In late winter and early spring, dynamics dominate the changes in Arctic temperatures. In austral spring and summer in the Antarctic, strong dynamical warming throughout the mid- to lower stratosphere acts to weaken the strong radiative cooling associated with the Antarctic ozone hole and is indicative of a strengthening of the Brewer–Dobson circulation. This dynamical warming is a significant term in the thermal budget over much of the Antarctic summer stratosphere, including in regions where strong radiative cooling due to ozone depletion can still lead to net cooling despite dynamical terms. Quantifying the contributions of changes in radiation and dynamics to stratospheric temperature trends is important for understanding how anthropogenic forcings have affected the historical trends and necessary for projecting the future.National Science Foundation (U.S.) (NSF Grant 1419667

Fundamental differences between Arctic and Antarctic ozone depletion

Antarctic ozone depletion is associated with enhanced chlorine from anthropogenic chlorofluorocarbons and heterogeneous chemistry under cold conditions. The deep Antarctic “hole” contrasts with the generally weaker depletions observed in the warmer Arctic. An unusually cold Arctic stratospheric season occurred in 2011, raising the question of how the Arctic ozone chemistry in that year compares with others. We show that the averaged depletions near 20 km across the cold part of each pole are deeper in Antarctica than in the Arctic for all years, although 2011 Arctic values do rival those seen in less-depleted years in Antarctica. We focus not only on averages but also on extremes, to address whether or not Arctic ozone depletion can be as extreme as that observed in the Antarctic. This information provides unique insights into the contrasts between Arctic and Antarctic ozone chemistry. We show that extreme Antarctic ozone minima fall to or below 0.1 parts per million by volume (ppmv) at 18 and 20 km (about 70 and 50 mbar) whereas the lowest Arctic ozone values are about 0.5 ppmv at these altitudes. At a higher altitude of 24 km (30-mbar level), no Arctic data below about 2 ppmv have been observed, including in 2011, in contrast to values more than an order of magnitude lower in Antarctica. The data show that the lowest ozone values are associated with temperatures below −80 °C to −85 °C depending upon altitude, and are closely associated with reduced gaseous nitric acid concentrations due to uptake and/or sedimentation in polar stratospheric cloud particles

Observed connections of Arctic stratospheric ozone extremes to Northern Hemisphere surface climate

We present observational evidence for linkages between extreme Arctic stratospheric ozone anomalies in March and Northern Hemisphere tropospheric climate in spring (March–April). Springs characterized by low Arctic ozone anomalies in March are associated with a stronger, colder polar vortex and circulation anomalies consistent with the positive polarity of the Northern Annular Mode/North Atlantic Oscillation in March and April. The associated spring tropospheric circulation anomalies indicate a poleward shift of zonal winds at 500 hPa over the North Atlantic. Furthermore, correlations between March Arctic ozone and March–April surface temperatures reveal certain regions where a surprisingly large fraction of the interannual variability in spring surface temperatures is associated with interannual variability in ozone. We also find that years with low March Arctic ozone in the stratosphere display surface maximum daily temperatures in March–April that are colder than normal over southeastern Europe and southern Asia, but warmer than normal over northern Asia, adding to the warming from increasing well-mixed greenhouse gases in those locations. The results shown here do not establish causality, but nevertheless suggest that March stratospheric ozone is a useful indicator of spring averaged (March–April) tropospheric climate in certain Northern Hemispheric regions.National Science Foundation (U.S.) (AGS-1539972

Emergence of healing in the Antarctic ozone layer

Industrial chlorofluorocarbons that cause ozone depletion have been phased out under the Montreal Protocol. A chemically driven increase in polar ozone (or “healing”) is expected in response to this historic agreement. Observations and model calculations together indicate that healing of the Antarctic ozone layer has now begun to occur during the month of September. Fingerprints of September healing since 2000 include (i) increases in ozone column amounts, (ii) changes in the vertical profile of ozone concentration, and (iii) decreases in the areal extent of the ozone hole. Along with chemistry, dynamical and temperature changes have contributed to the healing but could represent feedbacks to chemistry. Volcanic eruptions have episodically interfered with healing, particularly during 2015, when a record October ozone hole occurred after the Calbuco eruption.National Science Foundation (U.S.) (FESD Grant OCE-1338814)National Science Foundation (U.S.). Atmospheric Chemistry Program (Grant 1539972

Scientific issues related to the cytology proficiency testing regulations

The member organizations of the Cytology Education and Technology Consortium believe there are significant flaws in current cytology proficiency testing regulations. The most immediate needed modifications include lengthening the required testing interval, utilizing stringently validated and continuously monitored slides, changing the grading scheme, and changing the focus of the test from the individual to laboratory level testing. Integration of new computer-assisted and located-guided screening technologies into the testing protocols is necessary for the testing protocol to be compliant with the law

Risk of miscarriage with bivalent vaccine against human papillomavirus (HPV) types 16 and 18: pooled analysis of two randomised controlled trials

Objective To assess whether vaccination against human papillomavirus (HPV) increases the risk of miscarriage

Short term persistence of human papillomavirus and risk of cervical precancer and cancer: population based cohort study

Objective To evaluate the cumulative incidence of cervical intraepithelial neoplasia II or worse (grade II+) or cervical intraepithelial neoplasia grade III+ after short term persistence of prevalently detected carcinogenic human papillomavirus (HPV)

DIAPH3 Governs the Cellular Transition to the Amoeboid Tumour Phenotype

Therapies for most malignancies are generally ineffective once metastasis occurs. While tumour cells migrate through tissues using diverse strategies, the signalling networks controlling such behaviours in human tumours are poorly understood. Here we define a role for the Diaphanous-related formin-3 (DIAPH3) as a non-canonical regulator of metastasis that restrains conversion to amoeboid cell behaviour in multiple cancer types. The DIAPH3 locus is close to RB1, within a narrow consensus region of deletion on chromosome 13q in prostate, breast and hepatocellular carcinomas. DIAPH3 silencing in human carcinoma cells destabilized microtubules and induced defective endocytic trafficking, endosomal accumulation of EGFR, and hyperactivation of EGFR/MEK/ERK signalling. Silencing also evoked amoeboid properties, increased invasion and promoted metastasis in mice. In human tumours, DIAPH3 down-regulation was associated with aggressive or metastatic disease. DIAPH3-silenced cells were sensitive to MEK inhibition, but showed reduced sensitivity to EGFR inhibition. These findings have implications for understanding mechanisms of metastasis, and suggest that identifying patients with chromosomal deletions at DIAPH3 may have prognostic value